Power Engineering 3B2 Chapter 11
Exam Questions with Correct Answers
When the pressure difference across a capillary tube is increased:
a. The flow of refrigerant increases.
b. The flow of refrigerant decreases.
c. The pressure of the refrigerant increases.
d. The pressure of the refrigerant decreases.
e. There is no change in the flow rate. - Answer-a
The king valve on an ammonia vapor compression system serves as a:
a. Refrigerant control valve.
b. Valve to connect the ammonia drum when charging the
system.
c. Brine control valve.
d. Master isolation shut-off valve.
e. The condenser flow control. - Answer-d
The automatic expansion valve is controlled by:
a. A transmitter.
b. The evaporator pressure.
c. Capillary action.
d. The refrigerant level.
e. The king valve. - Answer-b
The thermostatic expansion valve controls refrigerant flow by:
a. The liquid level in the condenser.
b. A temperature sensor at the evaporator inlet.
c. The evaporator pressure.
d. The liquid level in the evaporator.
e. A temperature sensor at the evaporator outlet. - Answer-e
The emergency discharge line on refrigeration systems shall:
a. Be connected directly to the top of the receiver or other vessel
used for storing the refrigerant
b. Be connected to the compressor
c. Have two valves connected to charging drum
d. Be connected directly to the top of the condenser and the
compressor
e. Have two return bends in the piping. - Answer-a
A capillary tube is mainly used on:
a. Large industrial refrigeration units.
b. Small household systems.
, c. Ammonia systems.
d. Lithium bromide units.
e. Absorption systems. - Answer-b
The high-side float is usually installed on the:
a. Liquid receiver or may act as a float chamber itself.
b. Evaporator inlet.
c. Condenser .
d. Line between the compressor and condenser.
e. Line between the condenser and receiver. - Answer-a
The capillary tube has a:
a. Very small diameter.
b. Medium sized diameter.
c. Large diameter.
d. Convergent-divergent cross-section.
e. Concaved cross-sectional area. - Answer-a
The emergency valve on ammonia systems should be:
a. Located near the compressor
b. Between emergency line and the evaporator
c. Located outside the building
d. Near the fire alarm
e. Located at the exit leading to the outside of the building. - Answer-c
The starting and stopping of the compressor is normally done automatically by means
of:
a. A pressure-limiting device.
b. An automatic low pressure cut out.
c. Either a temperature actuated control or a pressure-actuated control.
d. A rheostat.
e. A heat sensor in the evaporator. - Answer-c
Refrigeration condenser cooling water is usually controlled by:
a. Level controls.
b. Cooling tower demands.
c. Compressor discharge pressure.
d. Hand operated gate valves.
e. The level in the receiver. - Answer-c
A low-pressure control in a refrigerating system can be used for:
a. Condenser pressure control.
b. Starting and stopping the compressor.
c. Purging non-condensable gases.
d. Keeping the receiver pressure from getting too high.
e. Evaporator pressure control. - Answer-b
Exam Questions with Correct Answers
When the pressure difference across a capillary tube is increased:
a. The flow of refrigerant increases.
b. The flow of refrigerant decreases.
c. The pressure of the refrigerant increases.
d. The pressure of the refrigerant decreases.
e. There is no change in the flow rate. - Answer-a
The king valve on an ammonia vapor compression system serves as a:
a. Refrigerant control valve.
b. Valve to connect the ammonia drum when charging the
system.
c. Brine control valve.
d. Master isolation shut-off valve.
e. The condenser flow control. - Answer-d
The automatic expansion valve is controlled by:
a. A transmitter.
b. The evaporator pressure.
c. Capillary action.
d. The refrigerant level.
e. The king valve. - Answer-b
The thermostatic expansion valve controls refrigerant flow by:
a. The liquid level in the condenser.
b. A temperature sensor at the evaporator inlet.
c. The evaporator pressure.
d. The liquid level in the evaporator.
e. A temperature sensor at the evaporator outlet. - Answer-e
The emergency discharge line on refrigeration systems shall:
a. Be connected directly to the top of the receiver or other vessel
used for storing the refrigerant
b. Be connected to the compressor
c. Have two valves connected to charging drum
d. Be connected directly to the top of the condenser and the
compressor
e. Have two return bends in the piping. - Answer-a
A capillary tube is mainly used on:
a. Large industrial refrigeration units.
b. Small household systems.
, c. Ammonia systems.
d. Lithium bromide units.
e. Absorption systems. - Answer-b
The high-side float is usually installed on the:
a. Liquid receiver or may act as a float chamber itself.
b. Evaporator inlet.
c. Condenser .
d. Line between the compressor and condenser.
e. Line between the condenser and receiver. - Answer-a
The capillary tube has a:
a. Very small diameter.
b. Medium sized diameter.
c. Large diameter.
d. Convergent-divergent cross-section.
e. Concaved cross-sectional area. - Answer-a
The emergency valve on ammonia systems should be:
a. Located near the compressor
b. Between emergency line and the evaporator
c. Located outside the building
d. Near the fire alarm
e. Located at the exit leading to the outside of the building. - Answer-c
The starting and stopping of the compressor is normally done automatically by means
of:
a. A pressure-limiting device.
b. An automatic low pressure cut out.
c. Either a temperature actuated control or a pressure-actuated control.
d. A rheostat.
e. A heat sensor in the evaporator. - Answer-c
Refrigeration condenser cooling water is usually controlled by:
a. Level controls.
b. Cooling tower demands.
c. Compressor discharge pressure.
d. Hand operated gate valves.
e. The level in the receiver. - Answer-c
A low-pressure control in a refrigerating system can be used for:
a. Condenser pressure control.
b. Starting and stopping the compressor.
c. Purging non-condensable gases.
d. Keeping the receiver pressure from getting too high.
e. Evaporator pressure control. - Answer-b
